The present invention comprises a new and distinct cultivar of calla lily, botanically known as Zantedeschia sprengeri and hereinafter referred to by the cultivar name ‘Sunset Passion’.
‘Sunset Passion’ is a product of a planned breeding program, which had the objective of creating Zantedeschia hybrids for pot flower production in a wide range of colors with a large, classic flower shape. The breeding program began in 1989, and the new cultivar is a seedling selected from the crossing of a Zantedeschia sprengeri selection referred to as Z050779 (female parent, unpatented) with a Zantedeschia sprengeri selection referred to as Z030458 (male parent, unpatented). ‘Sunset Passion’ was selected in 2011 by the inventor in 't Zand, The Netherlands as one flowering plant within the progeny of the stated cross.
The first act of asexual reproduction of ‘Sunset Passion’ by tissue culture was performed by the inventor in September of 2011 in 't Zand, The Netherlands. Subsequent asexual reproductions by tissue culture at the same location have demonstrated that the combination of characteristics as herein disclosed for the new cultivar are retained and reproduced true to type through successive generations of asexual reproduction.
The following observations, measurements and comparisons describe plants grown from 12-14 weeks in 14 cm pots in 't Zand, The Netherlands under greenhouse conditions, which approximate those generally used in horticultural practice. Color references are made to The 2001 R.H.S. Colour Chart of The Royal Horticultural Society of London, except where general color terms of ordinary significance are used.
The present invention has not been evaluated under all possible environmental conditions. The phenotype may vary with variations in environment without a change in the genotype of the plant.
The following traits have been repeatedly observed and determined to be basic characteristics of ‘Sunset Passion’ which, in combination, distinguish this calla lily as a new and distinct cultivar:                1. Red/orange-colored spathes; and        2. Large inflorescences.        
Further, when compared to calla lily plant named ‘Orange County’ (U.S. Plant Pat. No. 27,863), the upper surface spathe color of ‘Orange County’ varies between Orange Group RHS 25A and 25B, whereas the upper surface spathe color of ‘Sunset Passion’ varies between Yellow-Orange Group RHS 21A and 21B, with a secondary color that varies between Orange-Red Group RHS 34A and N34B.
Table 1 provides similarities and differences of ‘Sunset Passion’ to its parents, Zantedeschia sprengeri selection Z050779 and Zantedeschia sprengeri selection Z030458.
TABLE 1‘Sunset Passion’SimilaritiesDifferencesZ050779Spathe shapeSpathe colorNumber of inflorescencesSpathe sizePlant heightZ030458Spathe sizeSpathe shapePlant heightSpathe color